enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Solar irradiance - Wikipedia

    en.wikipedia.org/wiki/Solar_irradiance

    In fact, under clear skies a solar panel placed horizontally at the north or south pole at midsummer receives more sunlight over 24 hours (cosine of angle of incidence equal to sin(23.5°) or about 0.40) than a horizontal panel at the equator at the equinox (average cosine equal to 1/ π or about 0.32).

  3. Approximations of π - Wikipedia

    en.wikipedia.org/wiki/Approximations_of_π

    In other words, begin by choosing a value for r. Consider all cells (x, y) in which both x and y are integers between − r and r. Starting at 0, add 1 for each cell whose distance to the origin (0, 0) is less than or equal to r. When finished, divide the sum, representing the area of a circle of radius r, by r 2 to find the approximation of π.

  4. Mathematics - Wikipedia

    en.wikipedia.org/wiki/Mathematics

    The Babylonians also possessed a place-value system and used a sexagesimal numeral system which is still in use today for measuring angles and time. [ 76 ] In the 6th century BC, Greek mathematics began to emerge as a distinct discipline and some Ancient Greeks such as the Pythagoreans appeared to have considered it a subject in its own right ...

  5. Age of the universe - Wikipedia

    en.wikipedia.org/wiki/Age_of_the_universe

    The value of the age correction factor, , is shown as a function of two cosmological parameters: the current fractional matter density and cosmological constant density . The best-fit values of these parameters are shown by the box in the upper left; the matter-dominated universe is shown by the star in the lower right.

  6. Logarithm - Wikipedia

    en.wikipedia.org/wiki/Logarithm

    Here M(x, y) denotes the arithmetic–geometric mean of x and y. It is obtained by repeatedly calculating the average (x + y)/2 (arithmetic mean) and (geometric mean) of x and y then let those two numbers become the next x and y. The two numbers quickly converge to a common limit which is the value of M(x, y). m is chosen such that

  7. Hexadecimal - Wikipedia

    en.wikipedia.org/wiki/Hexadecimal

    Hexadecimal (also known as base-16 or simply hex) is a positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen.

  8. Solar cycle - Wikipedia

    en.wikipedia.org/wiki/Solar_cycle

    TSI varies in phase with the solar magnetic activity cycle [72] with an amplitude of about 0.1% around an average value of about 1361.5 W/m 2 [73] (the "solar constant"). Variations about the average of up to −0.3% are caused by large sunspot groups and of +0.05% by large faculae and the bright network on a 7-10-day timescale [ 74 ] [ 75 ...

  9. Goldman equation - Wikipedia

    en.wikipedia.org/wiki/Goldman_equation

    Assuming that the system is symmetrical in the x and y directions (around and along the axon, respectively), only the z direction need be considered; thus, the voltage E m is the integral of the z component of the electric field across the membrane.